Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy

碩士 === 國立成功大學 === 物理學系 === 84 === Raman Scattering experiments on Lio.1Na0.9NbO3, Lio.12Na0.88NbO3 and Li0.15Na0.85NbO3 crystals have been performed in the temperature range from 300 to 77K. All the spectral lines in the Raman spectra can be assigned as the translational modes of cations Li+ and Na...

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Main Author: 戴學斌
Other Authors: 黃正雄
Format: Others
Language:zh-TW
Published: 1996
Online Access:http://ndltd.ncl.edu.tw/handle/83332219722255721540
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spelling ndltd-TW-084NCKU31980092016-02-05T04:16:32Z http://ndltd.ncl.edu.tw/handle/83332219722255721540 Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy 利用雷射拉曼光譜研究鈮酸鋰鈉晶體的相變溫度 戴學斌 碩士 國立成功大學 物理學系 84 Raman Scattering experiments on Lio.1Na0.9NbO3, Lio.12Na0.88NbO3 and Li0.15Na0.85NbO3 crystals have been performed in the temperature range from 300 to 77K. All the spectral lines in the Raman spectra can be assigned as the translational modes of cations Li+ and Na+ and the internal modes of NbO3 octahedron proposed by Ross. From the evolution of the spectral line in the Raman spectra at various temperatures, we conclude that phase transition of all three crystals occurs over a temperature range from 200 to 180K in the cooling process and at 280K in the heating process. The thermal hysteresis of the transition is about 80K, which can be attributed to the large structural change required at the transition. The lattice structure at room temperature were also studied by X-ray diffraction. The study shows that all three crystals have same lattice constants indicating that crystals LixNa1-xNbO3 with X=0.1, 0.12, 0.15 have same crystal structure. This conclusion is supported by the fact that all crystals have same phase transition temperatures from the Raman scattering studies. Previous studies have shown that crystals LixNa1-xNbO3 have orthorhombic symmetry for X up to 0.12. Our results reduce the X value to 0.1. For crystals with X≧0.1, the crystals lattice have tetragonal symmetry. 黃正雄 莊陽德 1996 學位論文 ; thesis 51 zh-TW
collection NDLTD
language zh-TW
format Others
sources NDLTD
description 碩士 === 國立成功大學 === 物理學系 === 84 === Raman Scattering experiments on Lio.1Na0.9NbO3, Lio.12Na0.88NbO3 and Li0.15Na0.85NbO3 crystals have been performed in the temperature range from 300 to 77K. All the spectral lines in the Raman spectra can be assigned as the translational modes of cations Li+ and Na+ and the internal modes of NbO3 octahedron proposed by Ross. From the evolution of the spectral line in the Raman spectra at various temperatures, we conclude that phase transition of all three crystals occurs over a temperature range from 200 to 180K in the cooling process and at 280K in the heating process. The thermal hysteresis of the transition is about 80K, which can be attributed to the large structural change required at the transition. The lattice structure at room temperature were also studied by X-ray diffraction. The study shows that all three crystals have same lattice constants indicating that crystals LixNa1-xNbO3 with X=0.1, 0.12, 0.15 have same crystal structure. This conclusion is supported by the fact that all crystals have same phase transition temperatures from the Raman scattering studies. Previous studies have shown that crystals LixNa1-xNbO3 have orthorhombic symmetry for X up to 0.12. Our results reduce the X value to 0.1. For crystals with X≧0.1, the crystals lattice have tetragonal symmetry.
author2 黃正雄
author_facet 黃正雄
戴學斌
author 戴學斌
spellingShingle 戴學斌
Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
author_sort 戴學斌
title Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
title_short Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
title_full Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
title_fullStr Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
title_full_unstemmed Studies of the LixNa1-xNbO3 crystals phase transition temperature by Laser Raman Spectroscopy
title_sort studies of the lixna1-xnbo3 crystals phase transition temperature by laser raman spectroscopy
publishDate 1996
url http://ndltd.ncl.edu.tw/handle/83332219722255721540
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